Dry ice in the air intake
William Stanley Calbeck
If you could create a dry ice chamber in the air intake hose to
cool down incoming air would this have the same effect as Nitrous?
William V. Byars III
>
>
>If you could create a dry ice chamber in the air intake hose to
>cool down incoming air would this have the same effect as Nitrous?
>
>
many fire *extinguishers*. Not much help to combustion, that. If you
isolated the dry ice from the air, and had it arranged such that it cooled
the incoming charge air, you'd effectively have more air going into the
engine. This would allow you to put in a bit more fuel, and you'd get a
bit more power. Nitrous is a good bit different than just cooling the air.
Nitrous oxide is a gas that is injected into the incoming charge air for
the engine. When you pump in nitrous, you also have to pump in a good bit
more fuel, depending on how much nitrous you use. When the charge burns in
the engine, the heat of combustion breaks the Nitrous oxide gas apart into
oxygen and nitrogen, it's component gases. The liberated oxygen then burns
the extra fuel you injected, producing a substantial power gain.
Just cooling the air won't have a big effect. Lowering the air
temp from the 100 degrees you get under the hood to the 60-70 degrees
outside the car produces around 15 or so horsepower (when you inject the
extra fuel the denser charge can burn). Cooling it more will probably
work up to a point, at which you get problems trying to vaporise the fuel,
problems with severe intake icing (the water in the air freezes), etc. It
would probably make a great intercooler medium though! Turbocharger/
supercharger outlet temps are generally anywhere from 150-300 degrees.
Cooling this back down to 100 degrees or so nets a huge efficiency gain,
allows yo to pump in more fuel, makes more power, lowers combustion temps
(a little, I think), and lowers exhaust temps, all good things.
Good luck with whatever you're experimenting with!
-William Byars
P.S. I may be wrong, would someone who knows correct me if I am, please?
William V. Byars III
Northwestern University, Evanston, IL. USA
ca...@merle.acns.nwu.edu
Brian Lucas
>From: ca...@merle.acns.nwu.edu (William V. Byars III)
>Subject: Re: Dry ice in the air intake
>Date: 10 Feb 1995 06:20:30 GMT
>In article <3he8oh$5...@schema.fiu.edu>, calb...@fiu.edu (William Stanley Calbeck) says:
>>
>>
>>If you could create a dry ice chamber in the air intake hose to
>>cool down incoming air would this have the same effect as Nitrous?
>>
>>
> Just cooling the air won't have a big effect. Lowering the air
>temp from the 100 degrees you get under the hood to the 60-70 degrees
>outside the car produces around 15 or so horsepower (when you inject the
>extra fuel the denser charge can burn). Cooling it more will probably
>work up to a point, at which you get problems trying to vaporise the fuel,
>problems with severe intake icing (the water in the air freezes), etc. It
>would probably make a great intercooler medium though! Turbocharger/
>supercharger outlet temps are generally anywhere from 150-300 degrees.
>Cooling this back down to 100 degrees or so nets a huge efficiency gain,
>allows yo to pump in more fuel, makes more power, lowers combustion temps
Funny thing is that this was keeping me awake last night. The idea I was
having was to pump a dry-ice acetone mixture (-78 degrees C) through a copper
coil in the air-intake., which, considering the amount of air going past the
coil, probably wouldn't bring it below 0 degrees (i.e. icing], but if you
worked it out right you might be able to push 10 degree air or so into the
chamber. Probably very gimmicky, but I'll take 15 HP (to tack onto the
whopping 130 I already got]. Think it would work?
-Brian Lucas
David Studly
William Stanley Calbeck <calb...@fiu.edu> wrote:
>
>If you could create a dry ice chamber in the air intake hose to
>cool down incoming air would this have the same effect as Nitrous?
No - it will cool the air down, but nitrous is essentially
"oxygen-in-a-bottle" that you are letting out in the intake manifold.
Since nitrous evaporates from a liquid to a gas at -127 F (or some
similarly cold temp if my number is wrong), it has the added effect of
being introduced into the engine at a low temperature.
-David Studly, david....@ohiou.edu
Kelly Murray
A couple weeks ago, racing at Gainesville Raceway, it was down into
the 30's and 40's (brrrrrr),and many racers were getting .2 second faster ET's
compared to their normal 70-degree ET's.
The 5.0 EFI guys are often using ice packs on their intake manifolds
and report significant increases in ET's from this.
At least in the past, racers would cool down the gasoline supply
by running it through a copper-coil in a dry-ice bath before
getting to the carb.
So I'd think a dry-ice intake charge cooling system would work
if you could prevent it from generating any restriction in the air movement.
It might be expensive and troublesome for the return you get.
It might be a neat trick for a bracket car that needs to run consistently,
to use the cooling to maintain a consistant air temperature by
varying how much cooling the system provides. Sounds like a hard problem.
--
-Kelly Murray (k...@prl.ufl.edu) <a href="http://www.prl.ufl.edu">
-University of Florida Parallel Research Lab </a>
Terence Liow
>If you could create a dry ice chamber in the air intake hose to
>cool down incoming air would this have the same effect as Nitrous?
DOn't quite think so. I don't know physics off the top of my head but
it's unlikely you will get the air/oxygen density that you would with
nitrous. You may get a little bit more power (due to a somewhat denser
air charge) but it won't be so much or for so long.
William V. Byars III
near-solid block of ice. You'd be better off routing your inlet air duct
to a point where it gets cool air directly from outside the car, like
down to the point just behind the bumper of the car. Then insulate the
air tubing with some reat-resistant wrap, something shiny like aluminum
foil (secure it well!) That would give some improvement. The 15hp number
was for a decent setup on a V-8 engined car. I don't know what results
you'd have, but if you can get air "rammed" into the inlet from the front
of the car, it'd get more air. Then, if you have fuel injection, the
computer will "sense" the extra air and feed it more fuel to burn. Then
you may see a power increase. If you've got a carburetor, you won't see
any increase unless you re-jet richer or you are already running too rich
and the extra air lets you burn the excess fuel. I've never done this
before myself, but all the books say try and get a good supply of cool
outside air for your engine.
As for using acetone to be the heat-transfer medium from the air
to the dry ice, like I said it'd be a great intercooler. It might give
some benefits alone, but you may end up with the air being too cold. If
you have the time and parts, give it a try, let us know. Sounds like it'd
work for, say, getting a bit more power for a dragstrip jaunt. I doubt the
dry ice would last all that long. Good luck experimenting!
William V. Byars III
Northwestern University, Evanston, IL. USA
ca...@merle.acns.nwu.edu
My opinions!
MJ HILL
: >If you could create a dry ice chamber in the air intake hose to
: >cool down incoming air would this have the same effect as Nitrous?
For a start the proportion of oxygen in N20 is around 30% whereas in air
it is only around 20%. Therefore if you just ran on nitrous in its
gaseous form you could expect around a 50% increase in power.
Another point is that N2O is stored in liquid form
which is around 660 times as dense as the gaseous form. The injection of
N20 into a motor increases the amount of oxygen which is available
substantialy while the amount of air that would be admitted without
nitrous remains about the same. This is due to the small amount of
volume of liquid nitrous needed to suplement the air.
In fact due to the cooling effect of the nitrous more air can be drawn in
with nitrous on than with it off. While your idea would produce an
increase in power. It would be nothing like the power increase that is
available with nitrous injection.
Martin
--
Southern Boy
talking about a coffee can approach which sounds similiar...
Take a coffee can and extend your fuel line so that you can wrap the line in a
coil around the inside of the can. Then, just before race time (I assume this
is street racing...), drop dry ice in the can and put the top on. The effect
I think he (they) were going for was to cool the gas down and force more gas
into the carb...never actually tried it.
And on a sadder note, we didn't bother to put Auntie-Freze in my '69 Cougar
Eliminator because the radiator was still leaking some. I found out
yesterday that it froze last week and popped a freeze plug. My Cougar is
dead! Yesterday my girlfriend and I sat in it and made FOMOCO engine noises
until we felt better...
Ah, well, just means I'll be yanking that 351C before I thought I was...gotta
sweet little 302 out of her Mustang to drop in while I'm rebuilding it, though.
________________________________________________________________________________
Carl....@scarolina.edu -
Writer, Poet, and Couch Tater by trade, Systems Integrator by financial
need; educated by college, loved by friends, misunderstood by peers,
and Southern, by God.
_______________________________________________________________________________
My Opinions are probably my own...